Actually correct Metamodel::EnumHOW's add_enum_value method description

Enums have a base type, not a value type.

Author: Kaiepi

doc/Type/Metamodel/EnumHOW.pod6

@@ -60,7 +60,7 @@ Returns the number of values.
 
     method enum_from_value(Metamodel::ClassHOW:D: $obj, $value)
 
-Given a value of the enum's value type, return the corresponding enum.
+Given a value of the enum's base type, return the corresponding enum.
 
     enum numbers <10 20>;
     say numbers.^enum_from_value(0)             # OUTPUT: 10